Ayres Knowledge Center The Floating Bulkhead | Page 8

Pine Grove – Bulkhead Being Installed
Confidential Client – Bulkhead Being Installed

Pine Grove Floating Bulkhead, Chester,
Pennsylvania Nuclear Power Plant
Bulkhead, Confidential Client
The Chester Water Authority in Pennsylvania has a
water supply reservoir created by the Pine Grove
Dam. The Water Authority cannot complete a full
open gate without releasing sediment into the
water supply reservoir, so it needed a bulkhead
to allow full gate testing, as well as maintenance
on the gates. The spillway consisted of two
44.17-foot-wide-by-30-foot-high (13.5-meter-
wide-by-9.1-meter-high) tainter gates. The six
caissons were each 5 feet (1.5 meters) high and
weighed approximately 21,000 pounds (9,525.4
kilograms). This bulkhead was installed as a one-
piece assembly, and the bays were fitted with
permanent stainless steel abutment seats. The client retained Crofton Diving
Company to replace an intake trash
rack and complete concrete repairs
at the nuclear power plant intake.
Crofton hired Ayres Associates to
design a floating bulkhead system
that could be used to dewater
each of the eight intake structures.
The bulkhead was designed so
that it could be used at one intake
structure and then either removed
from the water or moved to the
next intake structure for repairs.
The plant’s bulkhead system
consisted of 7 caissons, each 4.25
Confidential Client – Bulkhead Installed
feet (1.3 meters) tall and 22.83
feet (7 meters) long. Each caisson
weighed just over 11,000 pounds (4,989.5 kilograms) in the dry. The unique feature of the bulkhead was the need for
standoffs on the upstream side of the bulkhead. The standoffs were needed to give workers space to replace the cooling
water trash racks. This bulkhead was installed with the assistance of a crane. Although a crane is not necessary for
bulkhead installation, one was on site and aided in the installation in this case. Using the crane allowed easier installation
of the bulkhead as the crane controlled its descent and helped position the bulkhead on the cooling water intakes.

Pine Grove – Installed (Note Abutment Seat)

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